Watch glossary: C (part2)

C0Ck, see bridge.
COLIMAçONNAGE, see snailing.
COLUMN-WHEEL
Part of chronograph movements, governing the functions of various levers and parts of the chronograph operation, in the shape of a small-toothed steel cylinder. It is controlled by pushers through levers that hold and release it. It is a very precise and usually preferred type of chronograph operation.
COMPLICATION
Additional function with respect to the manual-winding basic movement for the display of hours, minutes and seconds. Today, certain features, such as automatic winding or date, are taken for granted, although they should be defined as complications. The main complications are moonphase, power reserve, GMT, and full calendar. Further functions are performed by the so-called great complications, such as split-second chronograph, perpetual calendar, tourbilon device, and minute repeater.
CORRECTOR
Pusher positioned on the case side that is normally actuated by a special tool for the quick setting of different indications, such as date, GMT, full or perpetual calendar.
COSC
Abbreviation of "Contrôle Officiel Suisse des Chronomètres" the most important Swiss institution responsible for the functioning and precision tests of movements of chronometers. Tests are performed on each individual watch at different temperatures and in different positions before a functioning bulletin and a chronometer certificate are issued, for which a maximum gap of -4..+4 seconds per day is tolerated.
CôTES CIRCULAIRES
Decoration of rotors and bridges of movements, whose pattern consists of a series of concentric ribs.
CôTES DE GENèVE
Decoration applied mainly to high-quality movements, appearing as a series of parallel ribs, realized by repeated cuts of a cutter leaving thin stripes.
COUNTDOWN TIMER
A function that lets the wearer keep track of how much of a pre-set period of time has elapsed. Some countdown timers sound a warning signal a few seconds before the time runs out. These are useful in events such all kinds of race.
COUNTER
Additional hand on a chronograph, indicating the time elapsed since the beginning of the measuring. On modern watches the second counter is placed at the center, while minute and hour counters have off-center hands in special zones, also called subdials.
CROWN
Usually positioned on the case middle and allows winding, hand setting and often date or GMT hand setting. As it is linked to the movement through the winding stem passing through a hole in the case. For waterproofing purposes, simple gaskets are used in water-resistant watches, while diving watches adopt screwing systems (screw-down crowns).
CROWN WHEEL
Wheel meshing with the winding pinion and with the ratchet wheel on the barrel-arbor.
CRYSTAL
The clean cover over the watch face. Three types of crystals are commonly found in watches: acrylic crystal, mineral crystal and sapphire crystal .